Fuse plug



Mar. 3, 192 s. 1,528,458

W. L. URQUHART 1 FUSE PLUG Filed July 17, 1922 myemor WlLLlAM UR UHART,

Patented Mar. 3, 1925.

; UNITED STATES 1,528,458 PATENT OFFlCE.

WILLIAM L. RQUHART, OF HARTFORD, CONNECTICUT.

rUsE

Application filed July 17,

To all whom it may concern:

Be it known that I, lVILLTAM L. UR-

QUHART, a subject of the King of Great Britain, and a resident of Hartford, in the county of Hartford and State of Connecticut, have invented new and Improved Fuse Plugs, of which the following is a specification. My invention relates to the class of vices that are interposed in an electric circuit to prevent, by destruction of the conductor, the transmission of an overload of electric current, and more especially to devices of this type in which-the dissolving element is inclosed within a case having a window therein, and an object of my invention, among others, is the production of a device of this class provided with means for disclosing with certainty the condition of the dissolving element, which device, in its entirety shall be of simple construction and which shall be effective in operation for producing the results desired.

One form of fuse plug embodying my invention and in the construction and use of which the objects herein set out, as well as others, may be attained, is illustrated in the accompanying drawings, in which- Figure 1 is an end view of my improved fuse plug.

Figure 2 is a side view of the same.

Figure 3 is a view, scale enlarged, in cross section through the plug on a. plane denoted by the dotted line 33 of Figure 4, the shutter being shown in its closed position.

Figure 4 is a view in central lengthwise section through my improved plug.

Figure 5 is a view through the shutter 011 a plane denoted by the dotted line 55 of Figure 3.

Figure 6 is a detail view in section through a portion of the shutter on a plane denoted by the dotted line 66 of Figure 3.

In the accompanying drawings the numeral 1O denotes the body of a fuse plug threaded at one end for insertion in a re ceptacle and having, upon this threaded portion, a terminal 11, and projecting through this end of the body a. conductor 12, said conductor and terminal being con nected by a fusible conductor 13, located in a chamber 14, which chamber is closed at that end opposite the conductor 12, by a cap 15 having an opening with awindow 16 through which the interior of the chamber may be observed. The general construction PLUG.

1922. Serial No. 575,635.

of the parts thus far set out is old and well known and will be readily understood by those skilled in the art and for this reason a further and detailed description is omitted herein.

In adapting my invention to this structure I provide a recess or recesses 17 in the wall of the chamber 14, and preferably at its upper end, and 'a groove or grooves 18 extending across the upper edge of the body into a groove 19 in the outer surface of the upper edge, and the drawings. The shutter support, preferably comprising two members. is secured to the upper edge of thebody, in the structure herein shown these members each comprising asupporting arm 20 located in a groove 18 and having a bent end 21 located in a groove 19. Each of these members also comprises a swinging arm 22 joined to the supporting arm by a hinge 23, that, in the construction herein shown is formed of a coiled spring located in a recess 17. A shutter 24 is secured to the swinging arms in any suitable manner. as herein shown clips 2526. out out and bent up from the material of the shutter, embracing the spring arms as more particularly shown in Figure 3 of the drawings, and it will be observed from this figure that the supporting and swinging arms are formed from a single piece of spring wire bent into suitable shape.

retainer 27. preferably in the form of a clip cut out and bent up from the material of the shutter, projects from said shutter into position to engage the fusible conductor 13 and thereby retain the shutter in its open position as shown in Figure 4 of the drawings. It will, therefore, readily be seen that when the fusible conductor or fuse 13 be comes disrupted, as by an overload of electric current, the retainer 27 will be released and the shutter under the impulse of its spring, will spring into position to close the window and thus indicate that the fuse has been blown.

My invention contemplates broadly the idea of a shutter for the window 16, which shutter is normally in position to close the window, or to expose the interior of the chamber. but which, upon melting of the fuse, will be swung into its opposite, or open or closed position, and thereby indicate the condition of the fuse within the chamber.

I claim 1. A fuse plug having a chamber containas shown in Figure 4: of

ing a fuse and having an opening into said chamber, supporting arms secured to said plug, swinging arms, coils connecting the supporting and swinging arms and forming a hinge connection therebetween, a shutter secured to said swinging arms, and means for connecting the shutter to said fuse to hold the shutter in position.

2. A fuse plug having a chamber con-V taining a fuse and having an opening into said chamber, supporting arms secured to said plug, swinging arms movably connected with the supporting arms, a shutter having clips for securing it to said swinging arms and means for connecting the shutter to said fuse to hold the shutter in position.

3. A fuse plug having a chamber containing a fuse and having an opening into said chamber, a U-shaped structure com prising supporting arms and swinging arms movab'ly connected with the supporting arms, a shutter secured to said swinging arms and means for connecting the shutter to said fuse to hold the shutter in position.

i. A fuse plug having a chamber containing a fuse and having anopening into said chamber, a supporting arm attached to said plug, a swinging arm movably attached to said supporting arm, and a shutter having clips on one face for securing it to the swing ing arm and a clip on the opposite face for securing it to said fuse.

5. A fuse plug having a chamber containing a fuse and having an opening into said chamber, supporting arms secured to said plug, swinging arms, springs connecting said supporting and swinging arms, the ends of the latter being joined, a shutter secured to said swinging arms, and means for connecting the shutter to said fuse to retain the shutter in position.

WILLIAM L. URQUHART. 

